1. Technical Field
The present invention relates to cars, walking apparatuses, and methods of determining shape of wheel.
2. Related Art
(1) (2)
Cars are already well known. The car is provided with a rotatable wheel and runs in a predetermined traveling direction by the wheel rotating (refer to JP-A-2002-227883).
By the way, a typical car is provided with the rotatable wheel and runs in a predetermined traveling direction by rotating the wheel. Such a car can make a turn by changing a direction of the wheel and can move backwards by rotating the wheel in an opposite direction, however, diversity of those movements is limited.
(3)
Walking apparatuses are well known. The walking apparatus is provided with legs for walking (refer to JP-A-2002-227883).
(4)
Cars having wheels that can rotate about a rotation axis are already well known. Furthermore, among the cars, there are cars provided with an attitude control mechanism for controlling the attitude of the car. Moreover, a wheel that is provided to the car has a contacting portion that can contact the ground while the car is moving and that is located lower than the rotation axis (refer to JP-A-2005-335513).
By the way, the attitude of the car needs to be able to change according to the movement of the car. For example, when the car performs a turning movement, a direction changing movement and so on, the attitude of the car needs to be inclined. In addition, the easier it is to incline the attitude of the car, the more the maneuverability of the car improves. For this reason, it is preferable that the contacting portion of the wheel is in a shape in which the attitude of the car can be easily changed to an inclined state.
On the other hand, the attitude of the car must be appropriately controlled by the attitude control mechanism. For example, the attitude of the car in the inclined state needs to be appropriately restored to an upright state by control of the attitude control mechanism. However, an attitude control ability of the attitude control mechanism has a limit, and depending on the shape of the contacting portion, there is a possibility that the attitude of the car is not maintained in an appropriate state. Therefore, the shape of the contacting portion needs to be a shape that takes into account the limit of the attitude control ability of the attitude control mechanism, so that the attitude of the car is maintained in an appropriate state.
(5)
There is already well known a car having a car body, and a wheel that is rotatably provided to the car body; an attitude of the car being restorable to a non-inclined state from an inclined state in which the car body and the wheel are inclined to the side, by control of an attitude control mechanism that controls the attitude of the car (refer to JP-A-2005-335513).
By the way, the shape of the wheel had been determined from the viewpoint of, for example, versatility, manufacturability, design, and the like.
However, the shape of the wheel influences the performance of the car, and in particular, whether or not the attitude of the car in the inclined state can be restored to the non-inclined state depends on the shape of the wheel. Therefore, in the case where the wheel with a shape which was determined from the viewpoint mentioned above is provided to the car, there is a possibility that the attitude of the car in the inclined state can not be appropriately restored to the non-inclined state by the control of the attitude control mechanism, and it becomes difficult to improve the performance of the car.